BODY SIZE AND ORIENTATION IN AGGREGATES OF TOAD TADPOLES BUFO-WOODHOUSEI

Tadpoles of the genus Bufo form large aggregates that exhibit many features of true schools. A computer image analysis system was used to analyze the position and orientation of tadpoles in photographs of aggregates in nature and under uniform laboratory conditions. A non-random spatial distribution with respect to body size was found within tadpole aggregates in the field. Aggregating tadpoles of different sizes orient in different directions in the laboratory and the field. Natural populations exhibit interaction between orientation and size more strongly than do laboratory populations. Size sorting is less precise for tadpoles than for most schooling fish.